If you already have the games you want to play, it would be useful to know which games and which version of the game you have, but in most cases the game files should just be there, or you may have an installer to run. An exception for example is the Mac CD LucasArts games that are distributed as a single Data file (and we have a tool to extract files from those, but since the DOS executable is not included you will not be able to run these on DOS anyway).